I just finished re-reading The Fionavar Tapestry trilogy this evening and, as with any book, the second read made me think about a lot of things. I always catch more of the little tricks, naturally. More importantly, my standards for authors are higher now, by virtue of my exposure to publishing and the "what it takes" of writing, than they were six or seven years ago when I first read it.
The important thing is how much it still worked. I still fundamentally enjoyed the book, I still nearly cried at the end and I still loved the writing and the slow build and release of tension, the battle construction, and so many other parts of the story and the style of its telling.